In recent years, scanning probe microscopes and electron microscopes using carbon nanotubes and other nanotubes as tips of probes have been proposed (Patent Document 1). Nanotubes are utilized in scanning probe microscopes as probe tips provided at the front ends of cantilevers and are utilized in electron microscopes as electron source probes. Patent Document 1 generally discloses a surface signal scan probe for electronic apparatuses and a method of producing the same. Electronic apparatuses include scanning probe microscopes. The probe disclosed in Patent Document 1 is produced utilizing carbon nanotubes and other various types of nanotubes. This is so as to try to realize a high resolution, high rigidity, and high bending modulus probe. In probe tips of scanning probe microscopes, research and studies have been conducted to increase the resolution from the viewpoint of how to make them sharper. In this sense, nanotubes may become important technology for the future.
Patent Document 1 (Japanese Patent Publication (A) No. 2000-227435) discloses an example of a method of producing a probe utilizing a carbon nanotube. A carbon nanotube is easy to produce, is inexpensive, and is suitable for mass production. The Patent Document 1 explains as an optimal method of production the method of production using electrophoresis to arrange a carbon nanotube at a metal plate of a holder etc. The carbon nanotube arranged at the holder is mounted at a mounting base end in the state attached to the holder. The mounting base end is for example the probe tip of an atomic force microscope. This mounting work (assembly work) is performed while positioning under observation by a scanning electron microscope (SEM). After the mounting work, the region including the mounting base end is formed with a coating film so as to bond the carbon nanotube to the mounting base end. As the method for forming the coating film, the method of using electron beam irradiation based on an SEM to form a carbon film, the method of breaking down reactive coating gas by an electron beam to form a coating film, and also the examples of CVD or PVD have been proposed. The carbon film formed by electron beam irradiation based on an SEM is usually called a “carbon contamination film”. Further, technology for forming a coating film at an intermediate part between the carbon nanotube and mounting base end to form a coating film and increase the carbon nanotube in thickness and strength has already been proposed.
According to the method of producing a probe utilizing a nanotube described in the above Patent Document 1, the problem arises that the produced probe is insufficient in strength. That is, when bonding the carbon nanotube to the mounting base end, the bonding coating film is formed via the carbon contamination film arising due to SEM observation, so the bonding strength becomes insufficient. Further, when strengthening a probe made using a carbon nanotube, since only one side is coated, sufficient strengthening is not possible. Further, since the bonding is via a carbon contamination film, the problem also arises that the conductivity is difficult to secure.
[Patent Document 1] Japanese Patent Publication (A) No. 2000-227435